5-Hy­droxy-7-phenyl-5-(prop-2-yn-1-yl)-5,6-dihydro-1-benzofuran-2(4H)-one monohydrate

In the title compound, C17H14O3·H2O, the six-membered ring, which adopts a half-chair conformation, makes a dihedral angle of 24.3 (2)° with the phenyl ring. In the crystal, the components are linked by O—H⋯O hydrogen bonds involving the water mol­ecule, and the hy­droxy and carbonyl groups of the organic compound. These inter­actions form a square-like supra­molecular synthon unit which propagates as chains parallel to the crystallographic b axis. A C—H⋯O interaction also occurs

A protein functionalization platform based on selective reactions at methionine residues.

Nature has a remarkable ability to carry out site-selective post-translational modification of proteins, therefore enabling a marked increase in their functional diversity1. Inspired by this, chemical tools have been developed for the synthetic manipulation of protein structure and function, and have become essential to the continued advancement of chemical biology, molecular biology and medicine. However, the number of chemical transformations that are suitable for effective protein functionalization is limited, because the stringent demands inherent to biological systems preclude the applicability of many potential processes2. These chemical transformations often need to be selective at a single site on a protein, proceed with very fast reaction rates, operate under biologically ambient conditions and should provide homogeneous products with near-perfect conversion2-7. Although many bioconjugation methods exist at cysteine, lysine and tyrosine, a method targeting a less-explored amino acid would considerably expand the protein functionalization toolbox. Here we report the development of a multifaceted approach to protein functionalization based on chemoselective labelling at methionine residues. By exploiting the electrophilic reactivity of a bespoke hypervalent iodine reagent, the S-Me group in the side chain of methionine can be targeted. The bioconjugation reaction is fast, selective, operates at low-micromolar concentrations and is complementary to existing bioconjugation strategies. Moreover, it produces a protein conjugate that is itself a high-energy intermediate with reactive properties and can serve as a platform for the development of secondary, visible-light-mediated bioorthogonal protein functionalization processes. The merger of these approaches provides a versatile platform for the development of distinct transformations that deliver information-rich protein conjugates directly from the native biomacromolecules

New alkene cyclopropanation reactions enabled by photoredox catalysis via radical carbenoids

We describe the recent emergence of a new approach for the synthesis of cyclopropane rings by means of photoredox catalysis. This methodology relies on the photocatalytic generation of radical carbenoids or carbenoid-like radicals as cyclopropanating species, and its characterized by an excellent functional group tolerance, chemoselectivity and ability to cyclopropane E/Z alkene mixtures with excellent stereocontrol. The mild reaction conditions and the employ of user-friendly reagents are highly attractive features that may find immediate use in academic and industrial laboratories

A transition-metal-free & diazo-free styrene cyclopropanation

An operationally simple and broadly applicable novel cyclopropanation of styrenes using gem-diiodomethyl carbonyl reagents has been developed. Visible-light triggered the photoinduced generation of iodomethyl carbonyl radicals, able to cyclopropanate a wide array of styrenes with excellent chemoselectivity and functional group tolerance. To highlight the utility of our photocyclopropanation, we demonstrated the late-stage functionalization of biomolecule derivatives

Catalytic Cleavage of C(sp2)−C(sp2) Bonds with Rh-Carbynoids

We report a catalytic strategy that generates rhodium-carbynoids by selective diazo activation of designed carbyne sources. We found that rhodium-carbynoid species provoke C(sp2)–C(sp2) bond scission in alkenes by inserting a monovalent carbon unit between both sp2-hybridized carbons. This skeletal remodeling process accesses synthetically useful allyl cation intermediates that conduct to valuable allylic building blocks upon nucleophile attack. Our results rely on the formation of cyclopropyl-I(III) intermediates able to undergo electrocyclic ring-opening, following the Woodward–Hoffmann–DePuy rules

A Stereoconvergent Cyclopropanation Reaction of Styrenes

The first stereoconvergent cyclopropanation reaction by means of photoredox catalysis using diiodomethane as methylene source is described. This transformation exhibits broad functional group tolerance and it is characterized by an excellent stereocontrol en route to trans-cyclopropanes regardless of whether E- or Z-styrene substrates were utilized

A Stereoconvergent Cyclopropanation Reaction of Styrenes

The first stereoconvergent cyclopropanation reaction by means of photoredox catalysis using diiodomethane as methylene source is described. This transformation exhibits broad functional group tolerance and it is characterized by an excellent stereocontrol en route to trans-cyclopropanes regardless of whether E- or Z-styrene substrates were utilized

Late-Stage Aryl C-H Bond Cyclopropenylation with Cyclopropenium Cations.

Herein, we disclose the first regio-, site- and chemoselective late-stage (hetero)aryl C-H bond cyclopropenylation with cyclopropenium cations (CPCs). The process is fast, operationally simple and showed an excellent functional group tolerance in densely-functionalized drug molecules, natural products, agrochemicals and fluorescent dyes. Moreover, we discovered that the installation of the cyclopropene ring in drug molecules could not only be used to shield against metabolic instability but also as a synthetic tool to reach medicinally-relevant sp3-rich scaffolds exploiting the highly-strained nature of the cyclopropene ring with known transformations